Fix map cache segfault, remove omt tripoints from map items' operations

[ShnitzelX2]

Summary

Bugfixes "fix map cache segfault, remove omt tripoints from map items' operations"

Purpose of change

Fix segfault on using a map cache item

Describe the solution

#79307 didn't account for location_variable_adjust, which uses tripoint_abs_ms and not tripoint_abs_omt, resulting in a tripoint type mismatch. When it was submitted, the maps I used just happened to work, I guess.

I realized that EOCs pretty much exclusively use tripoint_abs_ms, so trying to include more point types into EOCs was probably a bad idea. SPAWN_LOCATION_OMT using tripoint_abs_omt was therefore the outlier, so I changed it to record tripoint_abs_ms and project to _omt for reveal_map.

There are still issues with map-related items initializing their locations, see #79536

Describe alternatives you've considered

Serializing tripoint type and/or generalizing EOC tripoint use, either of which are overkill for maps alone

Testing

Used both a map cache with and without an initialized location, used a road map, verified TCLF badges still display correctly

For existing saves: because the item_var fields' names were changed, existing unread maps/badges you still want to use can be reinitialized by dropping them near their original spawn location; using them without doing this will default to the player's position without error

Additional context

[ZhilkinSerg]

This probably needs a migration from spawn_location_omt to spawn_location

[GuardianDll]

undefined EoC coordinate variables are treat as coordinates of one of the talker as fallback
which is bad and a lot of people told we need to remove it, but it saves us here, the game would just assume to reveal area around character